2003 c240 engine temp??
anyways when driving it usually stays around about 1/2' after 80C today it was 5C outside I was in stop and go traffic for about 45 mins and the engine temp got up to allmost the line betwwen 80 and 120c
ive never seen it go that high ever as soon as I got away from traffic it went back down to just above 80C BUT everytime i stopped at a light it went back up to allmost the line between 80C and 120C
NO coolant leaks no steaming no malfunctions
so is this normal temps??
Oh when i got home I put the winshie;d defrost on and the rad fan did come on so that works





You have problems if it stays at the 100C line or goes higher than that regularly.
87 deg is the absolute optimal operating temp but anywhere between 80-100C is normal, because lots of external factors influence engine temperature such as ambient temperature, traffic conditions etc.
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this is where it stays when im driving NO traffic. IE 15 min drive to work

this and the one below was after on the hywy for 20 mins at 120km then 5 mins city no traffic and 2 mins at idke for the pic

its never gone higher then the above 2 pics and to be honest ive had this car for 7 months and i never notuced it go above 80 and a hair before
I do not know the engine but could I ask a few of questions.
Do the fan/fans run when the engine temp guage is reading high?
At what temp does the fan cut in.?
Has the temperature guage been calibrated?.
Has the radiator been back flushed , degreased & descaled ?.
Are the radiator external heat transfer fins in good condition?
Is the radiator operating at the correct pressure ?.
Is there a difference in temp readings when the thermostat is removed completely?
Can you see/feel a good coolant flow anywhere in the system ?.
Have you always used a corrosion inhibitor ? Heavy scaling of engine jackets can limit heat transfer.A jacket water descaler could help but be careful of blockages occurring.
Is the coolant of the recommended consistancy ? ie too much additive can cause less heat transfer& higher temps.
I hope someone else can come up with a few suggestions.

I think that your thermostat is getting lazy - Benz thermostats fail wide open & you will get a P0128 to tell you that the car is running too cold. If it worries you change the stat. Otherwise wait for a CEL.
coolant last checked by MB in jan 07 car manufactured Dec 02
coolant appears to have some yellow (exact same colour as the coolant) goo in it
Now at 1st I thought maybe oil in the coolant but its not oil like its yellow and will disolve when run thru your fingers
car has 116,000Km on it I plan on doing a rad flush in the spring too cold right now
My coolant and oil levels never move
are the m112 engines know for head gasket problems??

coolant last checked by MB in jan 07 car manufactured Dec 02
coolant appears to have some yellow (exact same colour as the coolant) goo in it
Now at 1st I thought maybe oil in the coolant but its not oil like its yellow and will disolve when run thru your fingers
car has 116,000Km on it I plan on doing a rad flush in the spring too cold right now
My coolant and oil levels never move
are the m112 engines know for head gasket problems??
What does your service book say on coolant change servicing?
I would do a flush immediately.The cheese could be beginning to block your radiator.
id love to do the flush now but its -10C here and my ****** jeep takes up my garage which is also unheated so the flush has to wait till it warms up Im going to do the t-stat at the same time
I do not know the engine but could I ask a few of questions.
Do the fan/fans run when the engine temp guage is reading high?
At what temp does the fan cut in.?
Has the temperature guage been calibrated?.
Has the radiator been back flushed , degreased & descaled ?.
Are the radiator external heat transfer fins in good condition?
Is the radiator operating at the correct pressure ?.
Is there a difference in temp readings when the thermostat is removed completely?
Can you see/feel a good coolant flow anywhere in the system ?.
Have you always used a corrosion inhibitor ? Heavy scaling of engine jackets can limit heat transfer.A jacket water descaler could help but be careful of blockages occurring.
Is the coolant of the recommended consistancy ? ie too much additive can cause less heat transfer& higher temps.
I hope someone else can come up with a few suggestions.
Is it hard to change? Is it in a tight spot? Does anybody have a picture where it is located?
Mine has a clear fluid in it. what is the fuild called? where would be the cheapest place to buy it?
Do you just add the fluid in the white contanier? At what level in the containier should the fluid be at?
thank to all that help


I recommend using Benz genuine coolant or Zerex GO5
Dealer or rmeuropean
Zerex at most parts stores
Filling & level instructions in owners manual. If you don't have a manual download from forum. Fill to black top line on surge tank.
Last edited by Glyn M Ruck; Jul 21, 2010 at 09:52 PM.
anyways when driving it usually stays around about 1/2' after 80C today it was 5C outside I was in stop and go traffic for about 45 mins and the engine temp got up to allmost the line betwwen 80 and 120c
ive never seen it go that high ever as soon as I got away from traffic it went back down to just above 80C BUT everytime i stopped at a light it went back up to allmost the line between 80C and 120C
NO coolant leaks no steaming no malfunctions
so is this normal temps??
Oh when i got home I put the winshie;d defrost on and the rad fan did come on so that works
I just replaced the Thermostat and the coolant temperature sensor but no luck.
Anyone has any idea what could be wrong?
The car is a 1999 CLK 320.
Thanks



